An air-conditioning apparatus for multiple air-conditioners of building usage or the like is an apparatus in which, in general, an outdoor unit being one heat source device and indoor units individually provided in a plurality of air-conditioning target spaces are connected to one another, and the temperature of each of the air-conditioning target spaces is regulated. Conventionally, there is an apparatus in which, for example, heating or cooling of an air-conditioning target space(s) is performed by circulating a refrigerant of hydrofluorocarbon or the like between an outdoor unit placed outside of a house and indoor units placed in the air-conditioning target space(s) inside of the house, and by radiating heat or absorbing heat into/out of the air of the air-conditioning target space(s) by means of the indoor units through the refrigerant having been heated or cooled by the outdoor unit. Because, in this apparatus, a refrigerant circulates down to the indoor units due to the inherent structure, the refrigerant would be probable to leak inside of the air-conditioning target space(s).
For dealing therewith, there is an air-conditioning apparatus in which a relay unit is provided between an outdoor unit and indoor units; a refrigerant is circulated from the outdoor unit to the relay unit, and a heat medium such as water or the like is circulated from the relay unit to the indoor units; and heat is exchanged between the refrigerant and the heat medium by means of a heat-medium heat exchanger(s) included in the relay unit. In the relay unit, heat-medium flow-path changeover devices are further included; a heat medium heated by a heat-medium heat exchanger (hereinafter, referred to as a “heating-use heat medium”) is transported into an indoor unit performing a heating operation, and a heat medium cooled by a heat-medium heat exchanger (hereinafter, referred to as a “cooling-use heat medium”) is, into an indoor unit performing a cooling operation, respectively; and, by exchanging heat by means of the indoor units between these media and the air of air-conditioning target spaces each, a heating operation or a cooling operation can be achieved for every one of the air-conditioning target spaces (for example, Patent Document 1).
In an air-conditioning apparatus of Patent Document 1, in order to achieve a heating operation and a cooling operation for every one of indoor units, a heat-medium flow-path changeover device for changing over a kind of a heat medium (heating-use heat medium or cooling-use heat medium) is required in each one of all flow paths for transporting the heat medium from a relay unit into each of the indoor units, and a heat-medium flow-path changeover device for changing over a kind of a heat medium is required in each one of flow paths for returning the heat medium from each of the indoor units to the relay unit; namely, two of the heat-medium flow-path changeover devices are required in total per one indoor unit. Moreover, ambient temperature adjustment of an air-conditioning target space is performed by means of a flow-rate control of a heat medium transported from the relay unit into an indoor unit, so that one heat-medium flow-rate adjustment device is required per one indoor unit.
According to the manner described above, in a conventional air-conditioning apparatus, the apparatus requires two heat-medium flow-path changeover devices and one heat-medium flow-rate adjustment device for every one of indoor units; and required further are control components such as motors or the like for driving each of the devices, and/or various kinds of components for connection such as pipes for piping, fastening components, and the like.
To this end, there is a compound valve having a changeover function of two flow paths and a flow-rate adjustment function thereof (for example, refer to Patent Document 2). A heat-medium flow-path changeover device set forth in Patent Document 2 is constituted of a body for forming an outer block of the device, a flow-path changeover valve element inserted inside of the body and driven to switch over the flow paths, a flow-rate adjustment valve element for adjusting the quantity of flow, and motors for driving each of the valve elements. The body and the valve elements are manufactured by integrally molding them with a resin or the like.